The use of toilet flushing devices is known in the prior art. There is a growing consciousness of the need to conserve water, particularly in toilets where it is not always necessary to have a full flushing of the toilet. In order to conserve flushing water, attempts have been made at providing two flushing modes.
In conventional toilets, there is often provided in the water tank a tank-ball or flapper that can engage the annular seat formed by the flush pipe outlet. The tank-ball is linked by means of a lift chain to a lever pivotally mounted to the water tank inner wall. A flush actuator, usually a handle located outside the water tank controls the lever. As known in the art, upon the flush handle being pivoted from a rest position to an operative position, the lever will pull on the lift chain which in turn will raise the tank-ball from its seat to allow the water inside the water tank to flow into the toilet bowl. A water supply valve will allow water to be fed into the water tank until a float ball, connected to the supply valve, reaches a determined position in the water tank, at which point the supply valve will be closed. It is noted that the tank-ball is pivotally attached to the base of the overflow tube to pins, this simply as a matter of convenience since the overflow pipe extends closely adjacent to the flush pipe outlet. Also, the tank-ball is slightly buoyant, such that it will remain spaced from the flush pipe outlet while the water in the water tank flows out into the toilet bowl, but the combined action of the gravity and a suction effect from the flush pipe when the last water flows out through the flush pipe, will bias the tank-ball to engage its seat and seal the flush pipe outlet once the water tank is empty, to allow the water tank to be re-filled with water.
Indeed, toilets are conventionally made to allow a full flush to be accomplished, although this is not always necessary. Providing a selective dual flush system as contemplated by this invention would allow considerable water volumes to be saved.